Correlation of kinetic data of 1,3-dipolar cycloadditions of C-benzoyl-N-phenylnitrones with the homo energies of furan derivatives

1981 ◽  
Vol 46 (6) ◽  
pp. 1504-1512 ◽  
Author(s):  
Lubor Fišera ◽  
Anton Gáplovský ◽  
Hans-Joachim Timpe ◽  
Jaroslav Kováč
Keyword(s):  
Charge Transfer ◽  
Rate Constants ◽  
Kinetic Data ◽  
Empirical Equation ◽  
Dipolar Cycloaddition ◽  
Charge Transfer Complexes ◽  
Electron Affinities ◽  
Furan Derivatives ◽  
Dipolar Cycloadditions ◽  
Experimental Values

Application of PMO treatment to 1,3-dipolar cycloaddition of C-benzoyl-N-phenylnitrone with furan derivatives is described. Ionization potentials of 2-R-substituted furan derivatives (R = H, CH3, C2H5, CH2OH, CH2OCOCH3, C6H5, CHO) and 2,5-dimethylfurane representing experimental values of the HOMO energies have been determined from energies of the respective charge-transfer complexes with TCNE. Good correlation between IP and k2 rate constants indicates that the reaction is controlled by the LUMO(nitrone)/HOMO(furan deriv.) interaction. Electron affinities of the furan derivatives were determined from IP and energies of π-π* transitions using empirical equation ΔE(π-π*) = IP-EA-450.58 kJ mol-1.

Chemical behavior of charge-transfer complexes. VII. Solvolysis of alkyl arenesulfonate donors in the presence of aromatic acceptors

1978 ◽  
Vol 56 (4) ◽  
pp. 585-590 ◽  
Author(s):  
Allan K. Colter ◽  
Robert E. C. Turkos
Keyword(s):  
Acetic Acid ◽  
Charge Transfer ◽  
Kinetic Data ◽  
Association Constants ◽  
Charge Transfer Complexes ◽  
Chemical Behavior ◽  
Measurable Rate ◽  
Leaving Groups

Rates of solvolysis of several ethyl and 2-propyl arenesulfonates having π donor leaving groups were measured in the absence of accepter and in the presence of the π acceptors 1,3,5-trinitrobenzene (TNB) and 2,4,7-trinitrofluorenone (TNF). With four of the nine combinations investigated, added accepter produced small but measurable rate enhancements. Ester–TNF 1:1 association constants were measured spectrophotometrically at 20, 30, and 40 °C in acetic acid for 2-propyl 4-methoxy-1-naphthalenesulfonate (3b), 4,8-dimethoxy-1-naphthalenesulfonate (4), 3,7-dimethyl-1-naphthalenesulfonate (5), and 1-pyrenesulfonate (6). From the equilibrium and kinetic data, the reactivity of the 1:1 ester–TNF complex relative to that of the uncomplexed ester (kc/ku) in acetolysis at 85.73 °C was estimated to be lessthan 4.2 and 1.4 for 3b and 4, respectively, 4.4 ± 2.0 for 5, and 2.8 ± 0.4 for 6. The value of kc/ku for 6 determined from analysis of the kinetic data alone is 2.7 ± 0.8.

1,3-dipolar cycloaddition of C-benzoyl-N-phenylnitrone with furan derivatives. Anomalous dehydrogenation of cycloadducts with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

1980 ◽  
Vol 45 (12) ◽  
pp. 3546-3556 ◽  
Author(s):  
Lubor Fišera ◽  
Ján Leško ◽  
Miloslava Dandárová ◽  
Jaroslav Kováč
Keyword(s):  
Double Bond ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Furan Derivatives ◽  
Dipolar Cycloadditions

C-Benzoyl-N-phenylnitrone reacted with 2-R-substituted (R = phenyl, CH2OH, CH2OCOCH3, CH2SH) furan derivatives at 55 °C by a 1,3-dipolar cycloaddition reaction to the unsubstituted furan double bond to give mono- and bisadducts. 2,5-Dimethylfuran afforded monoadduct only. Dehydrogenations of monoadducts of 5-R-2-phenyl-3-benzoyl-3a,6a-dihydrofuro[3,2-c]isoxazolines with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone proceeded anomalously at 60 °C: dehydrogenation followed by electrocyclic opening afforded the corresponding ketonitrones. This method of dehydrogenation offers a new preparation of nitrones and further exemplifies the exploitation of products of 1,3-dipolar cycloadditions for synthetic purposes.

Charge transfer complexes of Schiff bases derived from 2-aminobenzothiazole with some acidic and nonacidic acceptors

1993 ◽  
Vol 71 (3) ◽  
pp. 318-324 ◽  
Author(s):  
Amany M. A. Ibrahim
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Charge Transfer ◽  
Magnetic Resonance ◽  
Proton Transfer ◽  
Schiff Bases ◽  
Electronic Absorption ◽  
Ionization Potentials ◽  
Charge Transfer Complexes ◽  
Electron Affinities ◽  
Nuclear Magnetic Resonance Spectra

When Schiff bases derived from 2-aminobenzothiazole were reacted with di- and trinitrobenzene derivatives as acidic and nonacidic acceptors in the ratio of 1:1, stable coloured charge transfer complexes (CTC's) were obtained. The structure and stoichiometry of the CTC's were studied by elemental analysis.as well as by electronic absorption and infrared and nuclear magnetic resonance spectra. The CTC's derived from nonacidic acceptors were stabilized via intermolecular π–π* and n–π* transitions while those derived from acidic acceptors were formed by intermolecular π–π* transitions and a proton transfer stabilized by resonance. The ionization potentials of the Schiff bases and the electron affinities of the nitrobenzene derivatives were calculated.

Magnetic properties of new charge-transfer complexes based on manganese porphyrins

1997 ◽  
Vol 90 (3) ◽  
pp. 407-413
Author(s):  
MARC KELEMEN ◽  
CHRISTOPH WACHTER ◽  
HUBERT WINTER ◽  
ELMAR DORMANN ◽  
RUDOLF GOMPPER ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Charge Transfer ◽  
Charge Transfer Complexes ◽  
Manganese Porphyrins

Charge Transfer Complexation Boosts Molecular Conductance Through Fermi Level Pinning

2018 ◽  
Author(s):  
Kun Wang ◽  
Andrea Vezzoli ◽  
Iain Grace ◽  
Maeve McLaughlin ◽  
Richard Nichols ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Single Molecule ◽  
Quantum Interference ◽  
Transmission Function ◽  
Scanning Tunneling ◽  
Charge Transfer Complexes ◽  
Tunneling Microscopy ◽  
Quantum Interference Effect ◽  
Single Molecule Junctions ◽  
Charge Transfer Complexation

We have used scanning tunneling microscopy to create and study single molecule junctions with thioether-terminated oligothiophene molecules. We find that the conductance of these junctions increases upon formation of charge transfer complexes of the molecules with tetracyanoethene, and that the extent of the conductance increase is greater the longer is the oligothiophene, i.e. the lower is the conductance of the uncomplexed molecule in the junction. We use non-equilibrium Green's function transport calculations to explore the reasons for this theoretically, and find that new resonances appear in the transmission function, pinned close to the Fermi energy of the contacts, as a consequence of the charge transfer interaction. This is an example of a room temperature quantum interference effect, which in this case boosts junction conductance in contrast to earlier observations of QI that result in diminished conductance.<br>

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